Variants of 800B Power Supply chassis

[Joseph W Strickland]

I see a current listing on ebay for an 800B Power Supply/FM IF/Audio Output chassis. I knew of some variations of this chassis from the early one released followed by a second version that incorporated the extra choke in the power supply circuit.

See http://www.ebay.com/itm/Vintage-EH-Scott-800B-Tube-Amplifier-6L6GC-...

However the one on ebay has the two chokes but there is no 0D3 regulator tube. Instead there appears to be a snap-in chrome plated hole plug where the 0D3 would normally be.  I have not found a schematic that matches that arrangement and the copy of the Service Notes that I have does not discuss such a version. Is this a valid schematic change and version of these units?

Joe

[Norman S Braithwaite]

If the auction to which you are referring is at the following link, it is the early version power amplifier with the OD3 tube located next to one of the 6L6 output tubes and with hum reducing modifications (added choke and 2-conducter FM cable).  The OD3 was relocated next to the FM IF strip in the late versions because some OD3 tubes would generate noise that was picked up by the phase splitter tube.

http://www.ebay.com/itm/Vintage-EH-Scott-800B-Tube-Amplifier-6L6GC-...

[Joseph W Strickland]

Norman;

OK, I see it now. Somehow I thought I was looking at two separate tubes for a driver and phase inverter. That is definitely an OD3 sitting to the right of the phase inverter tube. Thanks for the correction.

Joe